Aortic valve calcium score

AVC (Agatston) · Non-contrast ECG-gated CT; Agatston units of valve calcium

Normal range & thresholds

Severe AS very likely: ≥3000 AU (men), ≥1600 AU (women); likely: ≥2000 / ≥1200; unlikely: <1600 / <800 ^[5,6,80,172].

Pathophysiology

Calcium burden reflects anatomical severity independently of flow, so it adjudicates low-gradient AS where Doppler depends on flow ^[80,172]. Women develop severe AS with less calcium and more fibrosis — hence sex-specific thresholds.

Raised by

• Degenerative calcific AS, CKD/dialysis, ageing

Lowered by

• Bicuspid, rheumatic and radiation AS may be severe with less calcium (fibrotic)

Technique & pitfalls

• ECG-gated, non-contrast; exclude annulus and coronary calcium.

Pseudo-change & artefact

• Young/bicuspid/fibrotic valves (false low), mitral annular calcium contamination.

Treatment thresholds

• Confirms severe AS in paradoxical low-flow, low-gradient disease before intervention (ESC/EACTS 2025) ^[6].

Next step

• Heart Team; TAVI planning CT ^[36].

Drugs

None slow it.

Reversibility

Irreversible.